In December 2010 the roof of the Metrodome collapsed...you may remember this amazing video. One forward thinking company, Elite Sport Promotions Agency, was in contact with the owners of the Metrodome to see about buying the collapsed roof nearly immediately. They eventually were able to get a large amount of the dome and have made it into pieces that collectors can buy.
Here's the piece I bought at Uncommon Sportscards in Ritchfield. I picked up the 1987 design as the 1987 team made me a Minnesota Twins fan for life [1991 designs are available as well]. There are a whole bunch of different designs you can buy including reproductions of Homer Hankies and one in the shape of Minnesota.
Here's the certificate of authenticity that you get with the piece: